Bologna moved into Serie A's Champions League positions on Sunday after seeing off top-four rivals Roma 2-0, while Tijjani Reijnders inspired AC Milan to a 3-0 cruise over Monza.
Thiago Motta's side have been the revelation of the season so far and will finish the weekend fourth after another impressive display against depleted Roma.
Nikola Moro's 37th-minute strike and a Rasmus Kristensen own goal shortly after the break were enough for Bologna to claim their third win in four games and jump a point above champions Napoli and Fiorentina, who beat Verona 1-0 earlier in the day.
Motta has done a sensational job at Bologna after replacing Sinisa Mihajlovic in September last year, just over three months before his Serbian predecessor died following a long battle with leukaemia.
Bologna was Mihajlovic's last job in football and on Sunday home fans paid tribute with a big banner honouring the indelible memory he left over the three-and-a-half years he coached the club.
His picture was also shown on the stadium's screens in the presence of his wife Arianna and their children.
For Motta it was a big win against his former coach at Inter Milan Jose Mourinho, with whom he won the Serie A, Italian Cup and Champions League treble in 2010.
Mourinho, whose team missed key attackers Paulo Dybala and Romelu Lukaku, drop down to seventh, three points from Bologna.
Bologna are four points behind third-placed Milan who strolled to victory at the San Siro and moved six points behind Inter Milan ahead of the league leaders' clash at Lazio.
Milan's win came in large part thanks to a stellar display from Reijnders who set his team on the way to victory with a brilliant third-minute strike.
The Netherlands midfielder collected Christian Pulisic's pass just outside the area and then set off on a mazy dribble past five Monza defenders before poking his first home goal for Milan past Michele Di Gregorio.
Reijnders flies
Building on their midweek win at Newcastle United which ensured a spot in the Europa League knockouts, third-placed Milan moved up to 32 points.
"It's an honour to play here of course, to score here at the San Siro is very nice," said Reijnders, who believes Milan can still fight for the league title.
"Of course, you always have to believe, we are not finished yet. We are now halfway through the season and we have to keep going. Today was a good start."
Also on target for Stefano Pioli's team were teenage debutant Jan-Carlo Simic, who netted his first Milan goal shortly before the break, and Noah Okafor whose 76th-minute strike came following more fine play from Reijnders.
Born in Germany, centre-back Simic represents Serbia at youth international level.
The 18-year-old was brought on midway through the first half for Tommaso Pobega, the latest in a long line of Milan players to suffer a muscular injury this season.
He doubled the hosts' lead three minutes before half-time, ramming home Rafael Leao's low cross before charging off to celebrate.
And the San Siro faithful then began chanting Simic's name as his parents wept with joy in the stands.
"It's a dream for any kid to make your debut for a club like AC Milan and scoring on your debut is incredible," said Simic to Sky.
"But I've worked very hard for moments like this."
